Jennifer loaned me her copy of A Clearing in the Distance: Frederick Law Olmsted and America in the 19th Century by Witold Rybczynski (1999) before our trip to New York this summer. I didn't get a chance to crack the book before we left, but I read it just after we came back. This is one of those books with a topic that I wouldn't have really thought I'd be that into, but which ended up being fascinating. Definitely recommended.
Rybczynski's sub title "and America in the 19th Century" is no joke. This is certainly a biography, and the reader gets a full picture of Olmsted and his influence on the landscape of the United States and the formation of landscape architecture as a profession, but there is so much more than that: Civil War, 19th century gentlemen, German settlers in Texas, European tours, early New York commerce, the Chicago World's Fair, and just about everything else that a New England man of property and good breeding could be expected to dabble in.
Rather than overwhelming the reader with detail and context, the author expertly weaves Olmsted's personal narrative with everything that is going on around him into a nicely readable and extremely educational text. Pick this one up, dudes!